第一行安卓代码——从相册中选择照片8.3.2

8.3.1调用摄像头拍照
修改布局文件和MainActivity
见代码

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/activity_main"    android:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="match_parent">    <Button        android:id="@+id/take_photo"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="Take photo"/>    <Button        android:id="@+id/choose_from_album"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="Choose From Album"/>    <ImageView        android:id="@+id/picture"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"        /></LinearLayout>

import android.Manifest;import android.annotation.TargetApi;import android.content.ContentUris;import android.content.Intent;import android.content.pm.PackageManager;import android.database.Cursor;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.net.Uri;import android.os.Build;import android.provider.DocumentsContract;import android.provider.MediaStore;import android.support.annotation.NonNull;import android.support.v4.app.ActivityCompat;import android.support.v4.content.ContextCompat;import android.support.v4.content.FileProvider;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.ImageView;import android.widget.Toast;import java.io.File;import java.io.FileNotFoundException;import java.io.IOError;import java.io.IOException;public class MainActivity extends AppCompatActivity {    public static final int TAKE_PHOTO = 1;    public static final int CHOOSE_PHOTO = 2;    private ImageView picture;    private Uri imageUri;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        Button takePhoto = (Button) findViewById(R.id.take_photo);        Button chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);        picture = (ImageView) findViewById(R.id.picture);        takePhoto.setOnClickListener(new View.OnClickListener(){            @Override            public void onClick(View v) {                File outputImage = new File(getExternalCacheDir(), "output_image.jpg");                try {                        if(outputImage.exists() ) {                            outputImage.delete();                        }                    outputImage.createNewFile();                } catch (IOException e) {                    e.printStackTrace();                }                if(Build.VERSION.SDK_INT >= 24) {                    imageUri = FileProvider.getUriForFile(MainActivity.this,                            "com.example.cameraalbumtest.fileprovider", outputImage);                } else {                    imageUri = Uri.fromFile(outputImage);                }                Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");                intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);                startActivityForResult(intent, TAKE_PHOTO);            }        });        chooseFromAlbum.setOnClickListener(new View.OnClickListener(){            @Override            public void onClick(View v) {                if(ContextCompat.checkSelfPermission(MainActivity.this,                        Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {                    ActivityCompat.requestPermissions(MainActivity.this, new                    String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);                } else {                    openAlbum();                }            }        });    }    private void openAlbum() {        Intent intent = new Intent("android.intent.action.GET_CONTENT");        intent.setType("image/*");        startActivityForResult(intent, CHOOSE_PHOTO);    }    @Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        switch (requestCode) {            case TAKE_PHOTO:                if( resultCode == RESULT_OK ){                    try{                        Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));                        picture.setImageBitmap(bitmap);                    } catch (FileNotFoundException e){                        e.printStackTrace();                    }                }                break;            case CHOOSE_PHOTO:                if(resultCode == RESULT_OK){                    //判断版本型号                    if(Build.VERSION.SDK_INT >= 19) {                        //4.4以上版本                        handleImageOnKitKat(data);                    } else {                        handleImageBeforeKitKat(data);                    }                }                break;            default:                break;        }    }    @Override    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {        switch (requestCode) {            case 1:                if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {                    openAlbum();                } else {                    Toast.makeText(this, "You denide the permission", Toast.LENGTH_SHORT).show();                }                break;            default:                break;        }    }    @TargetApi(19)    private void handleImageOnKitKat(Intent data) {        String imagePath = null;        Uri uri = data.getData();        if(DocumentsContract.isDocumentUri(this, uri)) {            //如果是document类型的uri，则通过document id处理            String docId = DocumentsContract.getDocumentId(uri);            if("com.android.providers.media.documents".equals(uri.getAuthority())) {                Toast.makeText(this, "success01", Toast.LENGTH_SHORT).show();                String id = docId.split(":")[1];                String secletion = MediaStore.Images.Media._ID + "=" + id;                imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, secletion);            } else if("com.android.providers.downloads.documents".equals(uri.getAuthority())) {                Toast.makeText(this, "success02", Toast.LENGTH_SHORT).show();                Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(docId));                imagePath = getImagePath(contentUri, null);            }        } else if("content".equalsIgnoreCase(uri.getScheme())) {            Toast.makeText(this, "success03", Toast.LENGTH_SHORT).show();            //如果是content类型的Uri，则使用普通方式处理            imagePath = getImagePath(uri, null);        } else if("file".equalsIgnoreCase(uri.getScheme())) {            //如果是file类型的uri，则直接获取文件路径            Toast.makeText(this, "success04", Toast.LENGTH_SHORT).show();            imagePath = uri.getPath();        }        displayImage(imagePath);    }    private void handleImageBeforeKitKat(Intent data) {        Uri uri = data.getData();        String imagePath = getImagePath(uri, null);        displayImage(imagePath);    }    private String getImagePath(Uri uri, String seclection) {        String path = null;        //通过Uri和secletion来获取真实的图片路径        Cursor cursor = getContentResolver().query(uri, null, seclection, null, null);        if(cursor != null) {            if(cursor.moveToFirst()) {                path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));            }            cursor.close();        }        return path;    }    private void displayImage(String imagePath) {        if(imagePath != null) {            Bitmap bitmap = BitmapFactory.decodeFile(imagePath);            picture.setImageBitmap(bitmap);        } else {            Toast.makeText(this, "failed to get image", Toast.LENGTH_SHORT).show();        }    }}